Blood to be transfused into patients as required in certain medical procedures is normally obtained from a blood bank. This blood bank may be located at the hospital itself. Blood for the blood bank is provided by donors at various blood donation locations. The blood is drawn from the donor at such a location after making a physical check of the donor's health and the stored blood is typed and the specific type imprinted on a plastic container for the blood. It is then transferred to the blood bank.
At the blood bank, a second check of the blood type is normally made to make sure that the bag containing the blood is properly labeled. A specific type of blood is selected from the blood bank to match the patient's blood when a transfusion is to be made. The blood itself is delivered to the patient's room in the hospital and infused by way of a universal connector into a blood infusion tube or line extending to the patient's vein. The patient's blood type is normally checked by the nurse against the type blood in the blood source or bag to make sure that the blood will match.
While every effort is made to check carefully the blood type of the blood source and the blood type of the patient to prevent mismatches, mistakes still occur, usually at the site of the patient. Thus, a selected blood type is delivered to the patient's room but may be transfused into the wrong patient. This mistake more often occurs where there is a ward of several patients. In addition, sometimes a single patient will have multiple blood infusion lines extending to veins at different locations and there is an increased risk of connecting the source blood to an incorrect blood infusion line resulting in a mismatch when several such connecting lines are available.